An imaging device such as a digital video device or a digital camera forms an image of a subject on an imaging element such as a CCD (Charge Coupled Device), a CMOS (Complementary Metal-Oxide Semiconductor) or the like via a lens to convert the image of the subject into two-dimensional image information. A camera for measuring the distance to the subject is also proposed.
With reference to FIG. 16 and FIG. 17, an example of a compound eye system camera module for measuring a distance to a subject, which is disclosed in Patent Document 1, will be described. FIG. 16 is an exploded isometric view of the compound eye system camera module, and FIG. 17 is a cross-sectional view thereof.
Sequentially from the side of the subject, a aperture member 1121, a lens array 1122, a light shielding block 1123, an optical filter array 1124, and a semiconductor substrate 1125 are located. The semiconductor substrate 1125 has an imaging area 1126 formed thereon, and also has a driving circuit 1127 and a signal processing circuit 1128 formed thereon. The lens array 1122 includes a plurality of lenses. The aperture member 1121 has aperture (openings) at positions respectively matching the optical axes of the lenses of the lens array 1122. The optical filter array 1124 includes a plurality of optical filters in an area corresponding to each of the lenses of the lens array 1122. The optical filter array 1124 is formed of a plurality of types of optical filters having different spectral characteristics, and faces the imaging area 1126 with a space sandwiched therebetween. The light shielding block 1123 includes a light shielding wall 1123a at a position matching the border between each two adjacent lenses of the lens array 1122, namely, the border between each two adjacent optical filters of the optical filter array 1124.
The compound eye camera module having such a structure obtains a plurality of images having parallax, calculates a parallax amount from the images having parallax, and calculates a distance to the subject based on the parallax amount.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2003-143459